A new film to be screened next month will reveal the extent of Labour Party fears that the British National Party would seize the seat from the long-serving MP Margaret Hodge at this year's general election.
The Battle for Barking, a feature-length documentary for More4, shows that Labour strategists believed white working-class voters were deeply sympathetic to the BNP's anti-immigration message, and in parts of her constituency 70 per cent of voters were considering voting for the far-right party.
In one key scene, Gordon Brown's pollster Deborah Mattinson carefully explains that many voters in the borough are deeply hostile to Labour, which they blame for letting immigration run out of control.
For the first time, the party's unorthodox, but ultimately successful, strategy is revealed. Mrs Hodge, 66, was urged to represent herself as
a "battling granny", fighting against the odds, although she was advised never to make this explicit
-as she would make herself look "absurd".
Using this underdog strategy, she is slowly seen to re-build her support until, on the eve of the election she is able to announce to supporters that she os more popular than the Labour Party and they should sell her, rather than the government, to the people of Barking.
The film-makers spent a year following Mrs Hodge as she prepared to fight off the threat from BNP leader Nick Griffin, who believed support for his extreme-right views in her Barking constituency was strong enough to unseat her. Many in the Labour Party, including Mrs Hodge, felt he might be correct.
During an extremely testing year for the Barking MP, she not only had to fend off the extreme right, but had to cope with the death of her husband, judge Sir Henry Hodge, who lost his fight against leukaemia.
At the beginning of the film, Mrs Hodge, the daughter of Jewish immigrants from Germany, ponders the reasons the BNP leader has chosen to fight her seat. She concludes: "He hates women, he hates Jews and he hates immigrants - and I am all of them."
The increasingly bitter battle is recorded with great detachment by producer-director Laura Fairrie, who shows the BNP supporters as people with their own, sometimes tragic, stories to tell - including, in one case, the loss of a son in Afghanistan.
At the same time Mrs Hodge is shown to face her share of extreme prejudice, as when a BNP activist on election day tells her to " go back to Germany with the rest of the thieving MPs".
Ultimately, Margaret Hodge obliterated the BNP in Barking. She doubled her majority to 16,000 and pushed Nick Griffin into third place, behind the Tories.
In the election for Barking and Dagenham Council, at the same time, every BNP councillor lost their seat.
The Battle for Barking is a tribute to Mrs Hodge and her determination to show that it is possible to take the battle to the extreme right and win.